Cooking grills generally deploy a firebox enclosure for the combustion of fuel that have an upper rim. A grate is supported on the upper rim, and the grate in turn supports the food to be cooked. The fuel can be wood, pellets, charcoal, but may also be natural gas or liquid propane that is fed into a lower portion of the firebox via a manifold. The firebox typically has lower perforations to allow for the admission of air into the box to provide the oxygen that supports combustion of the fuel. The firebox and grate may be covered to conserve heat. One type of covering is a hinged overhead hood that extends from a lower rim at the periphery of the firebox upward to form a cavity for the food to be cooked or warmed. A hinge is typically located along a sides of hood and firebox to allow closure and trapping of heat and opening to add, evaluate, or turn foodstuffs during cooking as well as removal of the foodstuffs after cooking.
A vent or other perforation may be provided in a hood for purposes of venting hot combustion gas. The resulting hot combustion gas, including water (steam) and carbon dioxide, as well as heated air, rise upward through the grate to escape from an upper hood area via one or more vents.